Process for manufacturing the filaments of electric incandescent lamps.



No. 891,223. PATENTED JUNE 16, 1908. W. VON BOLTON. PROCESS FOR MANUFACTURING THE FILAMENTS OF ELEGTRIG I'NG'ANDESGENT LAMPS.

APPLICATION FILED FEB. 24, 1906.

ifl W I W wATFU -EYJ which it appertains to same.

and exact description of UNITED sTArEs PATENTOFFIOE.

WERNER VON BOLTON, OF OHA RLOTTENBURG,GERMANY, AKTIENGESELLSCHAFT, 'OF BERLIN,

PROCESS non MANUFACTURING THE FILAMENTS 011 ELECTRIC INGANDESG'ENT LAMrs. I

Specification of Letters Patent.

ASSIGN OR TO SIEMENS & HALSKE GERMANY.

Patented June 16, 1908.

Original application filed December 28, 1905, Serial No. 293,616. Divided and this application filed February 24,

' 1906. Serial N 0. 302,716.

To all whom 'it may concern:

Be it known that I, WERNER VON BoLToN,

Emperor, residing at Charlottenburg, near. Berlin, 10

m Liitrow, Germany, tain new and useful Improvements in Processes for Manufacturing the Filaments of Electric Incandescent Lamps; and I dov hereby declare the following to be a full, clear, the invention,such as will enable others skilled in the art to make and use the This invention relates to the manufacture of electric glow-lam s having a metallic filament which is incl dsed in a lass-bulb in vacuo. Its object is to provi e a\fil'ament which is refractory even at extraordinarily high temperatures, the economy of electric glow-lamps being. the eater the higherthe lighting conductor '0 electricity will be heated. I composethe filament of my improved electric lamp of substantially puretantalum metal.

inaso The invention consists in a. process for manufacturing the filament of such lamps.

To carry out my process I proceed as follows. As tantalum metal,- which is obtained in the usual wa exists in the form of amorphous powder, or at any Weldm process, order to obtain the metal id or compact stateg and I then form the filament by'ham'mering, forging, rolling, drawing or in any usual The finished filament maybe inclosed in a glass-bulb and the air contained therein may' be exhausted as is generally known in the art of manufacturing electric low-lamps. 4 In the accompanying lustration' I have shown, more or less diagrammatically, a lamp containing a filament formed according to this invention.-

In order to first obtain a coherent metallic body of tantalum, I mix the amorphous powder of tantalum metal with suitable binding substances which may be volatile, and I have found that paraflin is a good'and use-. ful binding substance for this purpose. resulting plastic mass may be pressed so as to take the shape which will be the most convenient for further treatment. I have also found by experiments that the amorphous have invented cerpressure.

rate in a non-coherent form, I first subject it to a condensingor mechanlcal way. 'b

homogeneous mass and powder of tantalum metal canbe transformed into a body sufi'iciently coherent to stand the further operations by very high .pressure so that in such case no binding substance is necessary. According to the pressure employed I obtain a more or less strong and coherent metallic body. v

\ I prefer to avoid the use of binding 'substances m forming the body, and to condense the amorphous powder merelyby suflicient substances are used, the aced in an oven to drive 11g substances; The bodies are then heated preferably by means of an electric current in the absence of air or. in vacuo orin an atmosphere of a gas havi upon tantalum or surrounded by an indifferentsubstance having no actionuppn tan- If organic bindin resulting body is p out the bindi ng no action talum. Under the influence of the heat roduced by the electric current finally a we ded or molten homogeneous metallic body is obtained which canbe hammered or forged or rolled or drawn to wire or known mechanical way. I the homogeneous metallicbody obtained in the above described manner to rodsorthe like of suitable. cross-section by pressing, rolling or the like, and then to draw wires from said rods.

treated inany prefer to reduce The incandescent bodies obtained accordmg above explained modifications of my process may be employed in the usual Way in a glassulb in vacuo.

To recapitulate,- converting pulverulent erent mass by pressure such mass in an indifierent environment, in

tantalum into a cothen passing through such mass an electric- -currerit of sufficient amperage to weld or fuse into a substantially finally drawing out the mass into filament form.

' The present case is a division application,. Ser. N 0. 293616.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare, that what I claim is:

1. The process of' reparing incandescent bodies from pulveru ent metallic tantalum which consists in, forming a'coherent body tlga/ particles together of co-pendirig to my said invention by either of themy process consists in or a binder, placing from such pulverulent metal, heating the body in an indifferent environment until the several particles of the metal metallicalls unite to form a homogeneous mass, and drawing such mass down to filament form.

' 2. The process of reparing incandescent bodies from pulveru ent metallic tantalum which consists in heating such tantalum in a state of granular agglomeration in an indifferent environment until the several particles thereof metallically unite to form a homogeneous mass and drawing such mass down to filament form.

3. The process of reparing incandescent bodies from pulveru ent metallic tantalum which consists in electrically heating such tantalum in a state of granular agglomeration in an indifferent environment until the several particles thereof metallically unite to form a homogeneous mass and drawing down such mass into filament form.

4. The process of reparing incandescent bodies from pulverui ent metallic tantalum which consists informing a coherent mass from such tantalum by pressure, electrically heating the mass in an indifferent environment until the several particles thereof me tallically unite to form a homogeneous mass and drawing down such mass into filament form.

In testimony whereof I have affixed my signature to this specification, in thepresence of two witnesses.

WoLnEMAR HAUPT, HENRY Plasma. 

